Adjustable stool



(.No Model.)

` R. E. HAMMER.

ADJUSTABLE STOOL.

Patented Mar. 1, 1887.

Ffc.

N. PUERS. Pholu-Lilhugmpher, washington, D. c.

UNITED STATES ROBERT EfHAMMER, OF PHILADELPHIA, PENNSYLVANIA.

ADJUSTABLE STOOL.

SPECIFICATION forming part of Letters Patent No. 358,660, dated March 1,1887.

Application filed February S, 1F86. Serial No. 191,191. (No model.)

.To @ZZ whom it may concern,.-

Be it known that I, ROBERT E. HAMMER, a citizen of the United States,and a resident of Philadelphia, Pennsylvania, have invented certainImprovements in Adjustable Stools, of which the following is aspecification.

My invention relates to that class of adjustable stools or seats inwhich the top of the stool is supported upon opposite frames, eachconsisting of two bars pivoted together at a point midway,orthereabout,betweeu their opposite ends, so that when said bars arecaused to turn upon their pivots the frameis expanded or contracted andthe top of the seat raised or lowered.

My invention consists of certain improvements in the construction ofadjustable stools of this class and in the devices for adjusting thestool and locking it in any desired position.

In the accompanying drawings, Figure lis a longitudinal section of astool construct-ed in aecordance with my invention, the upholstered topof the stool being removed 5 Fig. 2, a transverse section of Fig. 1 onthe line l 2; Fig. 8, a plan View of Fig. l; Figs. 4 and 5, detachedperspective views of parts of the structure, and Fig. 6 an enlargedsection of part ofthe locking device.

Each of the opposite supporting-frames ofthe stool consists of twocurved or inclined bars, A A, suitably connected and braced bytransverse rods a, and pivoted together at or about the center, thepivot-pins being formed in the present instance by the ends b of thecentral bar, a, of the frame.

The top frame, B,of the stool rests upon the rounded upper ends of thebars A A of the side frames, and said frameB isvertically confined tothe bars A by means of links d, secured to or forming part of transverseplates D, the opposite ends of which are adapted to grooves e in theside bars of the frame B. On

each plate D, at or about the center of thesame, is a depending lug, f,the lugs of the two plates being connected together by a spring, F, thetendency of which is to draw the plates D D toward each other, thismovement being transmitted by the links d to the upper ends of the barsA A of the supporting-frames, so that in the absence of any retainingdevice the spring would draw the upper ends of the bars A A together,and thus elevate the seat to the full height, while pressure upontheseat would overcome the tension ofthe spring and separate the upperends ot' the bars A A of each supportingframe, so as to lower the seatto the full extent. In order, however, to lock the seat at any desiredelevation, I provide each ol" the plates D with a projecting rack, g, apinion, h, engaging with the opposite racks, and being hung to a` stud,c, 011 a central transverse plate, G, secured to the top frame, B, ofthe stool. To suitable bearings on this plate G is adapted alockingbolt, H, which has a tooth, fi, adapted to engage with thc teethof the pinion lt and prevent the rotation of the same, a spring, m,acting upon the bolt and tending to cause the same to engage with thepinion, from which the bolt may be withdrawn, however, by means of anoperating-rod, n, which projects through an opening in the frame B ofthe stool, and

has a catch, p, for engagement with a retaining-plate, t, on said frame,the outer end of the rod having a ring or other suitable handle, w, bywhich it may be readily manipulated.

Thepinion 7L is held in position vertically on the stud `c by means ofthe locking-bolt, which passes transversely beneath the pinion andsupports the same, the use of a screw bolt or pin as a pivot for thepinion being thus rendered unnecessary and the fitting together of theparts somewhat simplied.

When it is desired to depress the stool, the rod o1, is iirst lifted soas to free its catch from the control ot' the plate t, and is then drawnoutward, thereby withdrawing the bolt H from engagement with the pinionh, the racks y being thereupon free to move in opposite directions whenpressure is exerted upon the seat sufiicient to cause the forcing apartof the upper ends ofthe bars A A of each supportingframe. When the stoolhas been depressed to the proper' extent, the rod n is released, so thatthe bolt H, under the influence of the spring m, again engages with andlocks the pinion lt, the rod n being at the same time retained byengagement of its catch p with the plate t.

When it is desired to raise the stool, the

locking-bolt is withdrawn in the same manner IOO vnecessary in orderthat the said racks may re-v tain a position parallel with the frame B,whatever the angle assumed by the bars A, and in the present instancethe plates D and links d providesuch a pivotal connection for the racks,

" in addition to their function of confining the frame B to the bars A,and this construction is preferred, although not absolutely essential tothe proper carrying out of my invention. The plates D also serve asmeans whereby the pull of the spring F is always eXertedin alinedirectly parallel with the line of thrust of the racks g.

Although I have shown and described my invention as applied to a stoolor seat, it will be evident that it can be applied as well to tables ordesks, the frame B in this case being secured to or forming part of thetop of said table or desk.

claim as my invention 1. The combination, in an adjustable stoolN orlike article of furniture, of a supporting frame consisting of pivotedbars, with the frame B, carried by said bars, rack-and-pinion mechanismreceiving movement from said bars, a locking bolt or catch movable intoor out of engagement with said pinion, and a spring acting upon theupper ends of said bars of the supporting-frame, and serving as a meansfor drawing said upper ends of the bars together tially as spccied.

2. The combination of the pivoted bars A, the frame B, carried thereby,the plates D, having racks g g and connected to the bars A, a piniongearing into said racks, a locking-bolt for said pinion, anoperating-rod connected to the bolt, anda retainer for said rod, allsubstantially as specified.

3. The combination of the pivoted bars A,

.the frame B, supported thereon, the plates D,

and thus elevating the frame B, all substan- In testimony whereofl havesigned my name to this specication in the presence of two subscribingwitnesses.

ROBERT E. HAMMER.

Witnesses:

WILLIAM D. CONNER, HARRY SMITH.

